Build: Update devDependencies & jsHint configuration

It's a good practice to list peerDependencies directly in package.json,
especially that current auto-installing behavior will go away in future
versions of npm: https://github.com/npm/npm/issues/5080

Also, jsHint plugin should search for proper .jshintrc files on its own;
current behavior integrated badly with IDEs in some cases.

cc @markelog